package com.mybatis.utils;

import java.io.IOException;
import java.io.InputStream;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

/**
 * @author qinjiasheng
 */
public class SqlSessionFactoryUtils {
	private final static Class<SqlSessionFactoryUtils> LOCK = SqlSessionFactoryUtils.class;
	private static SqlSessionFactory sqlSessionFactory = null;
	private SqlSessionFactoryUtils(){}

	private static SqlSessionFactory getSqlSessionFactory() {
		synchronized (LOCK) {
			if (sqlSessionFactory != null) {
				return sqlSessionFactory;
			}
			String resource = "mybatis-config.xml";
			InputStream inputStream;
			try {
				inputStream = Resources.getResourceAsStream(resource);
				sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
			} catch (IOException e) {
				e.printStackTrace();
				return null;
			}
		}
		return sqlSessionFactory;
	}

	public static SqlSession openSqlSession() {
		if (sqlSessionFactory == null) {
			getSqlSessionFactory();
		}
		return sqlSessionFactory.openSession();
	}
}
